X40626

The X40626 combines four popular functions, Power-on Reset Control, Watchdog Timer, Dual Supply Voltage Supervision, and Serial EEPROM Memory in one pack- age. This combination lowers system cost, reduces board space requirements, and increases reliability.

Applying power to the device activates the power on reset circuit which holds RESET active for a period of time. This allows the power supply and oscillator to stabi- lize before the processor can execute code.

The Watchdog Timer provides an independent protection mechanism for microcontrollers. When the microcontrol- ler fails to restart a timer within a selectable time-out interval, the device activates the RESET signal. The user selects the interval from three preset values. Once selected, the interval does not change, even after cycling the power.

The X40626's low V_CC detection circuitry protects the user's system from low voltage conditions, resetting the system when V_CC falls below the set minimum V_CC trip point. RESET is asserted until V_CC returns to properoperating level and stabilizes. Four industry standard Vtrip hresholds are available. However, Xicor's unique circuits allow the threshold to be reprogrammed to meet custom requirements or to fine-tune the threshold for applications requiring higher precision.

The memory portion of the device is a CMOS Serial^(TM) EEPROM array with Xicor's Block Lock  Protection. The array is internally organized as 64 bytes per page. The device features an 2-wire interface and software protocol2 allowing operation on an I C bus.


The X40626 utilizes Xicor's proprietary Direct Write  cell, providing a minimum endurance of 100,000 page write^(TM) cycles and a minimum data retention of 100 years.